Coupling members adapted for attachment to the end of hose and tubing for use in the transfer of fluids under pressure from one point to another are well known to the prior art. It is essential that the coupling member be installed on the end of the hose or tube so securely that it will not become detached in service even when the hose or tube is conducting fluids at high pressures, high temperatures and/or subjected to repetitive pressure or flexing cycles or axial strain conditions. The usual practice for attaching the coupling member to the end of the hose or tube has been to provide a fitting having a nipple or stem portion adapted to be inserted into the bore of the hose or tube and a substantially cylindrical shell adapted to surround the sheath of the hose or the outer surface of the tubing. After the coupling member has been installed loosely on the end of the hose it is placed in a swaging or crimping apparatus which reduces the diameter of the shell and compresses the hose wall between the nipple and the shell.
The heretofore available hose and tubing coupling member assemblies have not been entirely satisfactory for operating at high fluid pressures, high temperatures and/or subjected to repetitive pressure or flexing cycles or axial strain conditions. It has been proposed heretofore to provide an insert member between the shell and the hose or tube to fasten more securely the coupling member to the end of the hose or tubing. For example, the hose disclosed in U.S. Pat. No. 3,457,359 issued July 22, 1969 is provided with a flat element having one or more sharp prongs embedded in the wall of the hose. Also, in accordance with the disclosure in U.S. Pat. No. 2,314,000, a segmented insert member having barbs is provided between the nipple and the shell. The insert member has one end disposed against ridges on the nipple and the barbed members are disposed on the external surface of the hose with their barbs embedded in the hose wall. A hose having a somewhat similar insert member underlying the shell of the coupling member is disclosed in Swiss Pat. No. 101,231 published Sept. 15, 1923. Still other types of barbed insert members installed between the external surface of the hose and the shell of the coupling member have been proposed but they all have the same disadvantage of requiring the manufacture and assembly of an additional part for the coupling and they all present a problem of fastening the shell about the slick surfaced insert member so securely that the coupling is not blown from the end of the hose when the hose is operating under high pressure. The above noted references provide for the additional insert member to be disposed between the outer surface of the hose and the inner surface of a compressable or clamping member. An example of a coupling member having a segmented clamp-on type outer member having conical projections on the inner surface thereof is disclosed in U.S. Pat. No. 3,357,432 issued Dec. 12, 1967. A coupling member having a segmented clamp-on type outer member having annular ridges on the inner surface thereof and adapted to be attached to a hose by use of wedges is disclosed in U.S. Pat. No. 3,181,900 issued May 4, 1965. A further example of a coupling member having an outer shell having annular rings on the inner surface thereof is disclosed in U.S. Pat. No. 2,341,003 and coupling members whose outer shells have spaced holes therein so that the hose sheath might project therethrough upon compressing the shell are disclosed in U.S. Pat. No. 2,987,263 issued Apr. 4, 1961 and U.S. Pat. No. 2,810,594 issued Oct. 22, 1957.
The above referenced one-piece outer shell or compressable members have the disadvantage of having a complex segmented design requiring complicated and costly fabrication and do not provide for circumferentially spaced solid integral three-dimensional barbs on the inner wall of the outer shell or compressable member nor do they provide for a novel method of making an improved one-piece shell or compressable member for use in permanently attachable hose and tube coupling members hereinafter described.